The new law also gives marijuana shops the same authority that liquor stores have to confiscate fraudulent IDs from underage consumers. It passed unanimously in both chambers of the Legislature.

“Everyone came together on this,” said Rep. Daniel Kagan, a Denver Democrat who sponsored the law.

A pediatric emergency room physician from Children’s Hospital Colorado, Dr. George Sam Wang, joined the bill signing and said there’s anecdotal evidence of emergency rooms seeing more cases of youth marijuana overdoses.

“The most extreme cases we’ve seen are very young children who take a large amount of high potency products and get very sleepy, comatose and have difficulty breathing,” Wang said.

But Wang said that there’s not enough data to draw conclusions on the effect of recreational pot, and that more study is needed.

“We’ve only been experiencing this for a couple years,” Wang said.

Another new law signed Monday allows local governments that want to run criminal background checks on people working in the marijuana industry to submit fingerprints to the Colorado Bureau of Investigation. Everyone working in the industry already completes state-level background checks.

Asked whether the marijuana industry needs additional curbs – including a possible potency limit or new limits on edible pot – Hickenlooper said it was too soon to advocate for more sweeping changes.

“This is brand-new territory,” Hickenlooper said.

Some lawmakers have said they want to propose curbs on edible pot, but no such bill has yet been introduced.

In the states that allow marijuana, the total number of calls to poison control increased 30 percent each year for pot related issues.

Legislators are still mulling pot taxes. The first $40 million from pot excise taxes is devoted to education, but lawmakers will decide how to spend any additional tax revenue.

Rep. Dan Pabon, D-Denver, wants to see a task force of lawmakers and industry activists discuss the best way to spend excess tax revenue. He met with industry representatives Monday.

Among the ideas from industry representatives were more money for researching the health effects of cannabis and trying again to create a state-chartered bank to serve the industry.